Power operated rotary knives are widely used in meat processing facilities for meat cutting and trimming operations where it is desired to remove material, for example, a layer of fat, from a product, for example, an untrimmed piece of meat. Power operated rotary knives also have application in a variety of other industries where cutting and/or trimming operations need to be performed quickly and with less effort than would be the case if traditional manual cutting or trimming tools were used, e.g., long knives, scissors, nippers, etc. By way of example, power operated rotary knives may be effectively utilized for such diverse tasks as taxidermy and cutting and trimming of elastomeric or urethane foam for a variety of applications including vehicle seats.
Power operated rotary knives typically include a handle assembly and a head assembly attachable to the handle assembly. The head assembly includes an annular blade housing and an annular rotary knife blade supported for rotation by the blade housing. The annular rotary knife blade of a conventional power operated rotary knife defines a closed loop cutting surface for cutting or trimming material from a product wherein the rotating blade contacts and cuts the material, thereby removing the material from the product. The cut or trimmed material moves away from a cutting edge at one end of the rotary knife blade. An inner wall of the rotary knife blade defines a central, open region of the blade. The cut or trimmed material moves away from the cutting edge, travels or traverses along the inner wall and through the central, open region of the blade before exiting the blade at an end opposite the cutting edge.
The rotary knife blade is typically rotated by a drive assembly which may include a pneumatic or electric motor disposed in an opening or throughbore defined by handle assembly. The pneumatic or electric motor may include a drive shaft that engages and rotates a pinion gear supported by the head assembly. The pinion gear, in turn, engages and rotatably drives the annular rotary knife blade. Gear teeth of the pinion gear engage mating gear teeth formed on an upper surface of the rotary knife blade to rotate the blade. Alternatively, the drive assembly may include a flexible shaft drive assembly extending through an opening in the handle assembly. The shaft drive assembly engages and rotates a pinion gear supported by the head assembly. The flexible shaft drive assembly includes a stationary outer sheath and a rotatable interior drive shaft. The shaft drive assembly is coupled to and driven by a pneumatic or electric motor which is remote from the handle assembly.
Upon rotation of the pinion gear by the drive shaft of the flexible shaft drive assembly, the annular rotary blade rotates within the blade housing at a high RPM, on the order of 900-1900 RPM, depending on the structure and characteristics of the drive assembly including the motor, the shaft drive assembly, and a diameter and the number of gear teeth formed on the rotary knife blade. Conventional power operated rotary knives are disclosed in U.S. Pat. No. 6,354,949 to Buis et al., U.S. Pat. No. 6,751,872 to Whited et al., U.S. Pat. No. 6,769,184 to Whited, and U.S. Pat. No. 6,978,548 to Whited et al., all of which are assigned to the assignee of the present disclosure and all of which are incorporated herein in their respective entireties by reference.
When material is cut or trimmed by a rotary knife blade, the removed material (that is, the cut or trimmed material) moves or travels away from a cutting edge of the blade and through the central, open region defined by the knife blade inner wall and exits the opposite end of the rotary knife blade. Upon exiting the rotary knife blade, the removed material will, depending on the position of the power operated rotary knife and the product, either fall back upon a trimmed or an untrimmed portion of the product being cut or trimmed or fall to a surface a workstation where the cutting or trimming operation is being performed. For certain applications, it may be desirable to have a vacuum attachment to a power operated rotary knife to remove, via suction, the removed material such that the removed material does not fall onto the product or fall to the work station surface, but instead is routed away from trimmed product after being cut or trimmed from the product. In certain cutting or trimming operations, the removed material is undesirable and it is desired to immediately physically separate the removed material from the product, for example, if the removed material is unwanted fat tissue to be removed from a steer carcass during a hot defatting process or a contaminated/bruised tissue region of a poultry or pig carcass, it would be desirable to use suction to route the removed/unwanted tissue from the carcass immediately upon cutting or trimming the unwanted tissue to a collection receptacle for disposal purposes and/or to avoid contamination of the carcass by the removed tissue. On the other hand, in certain cutting or trimming operations, the removed material is highly desirable or valuable, for example, removal of desirable oyster meat from a poultry carcass. Again, the suction of a vacuum attachment will route the desirable removed tissue (oyster meat) to a collection receptacle for collection of the desirable removed tissue.
Power operated rotary knives including vacuum attachments are disclosed in, for example, U.S. Pat. No. 6,857,191 to Whited et al. and U.S. Published Application No. US 2004/0211067 to Whited et al., both of which are assigned to the assignee of the present disclosure.